I performed The Messiah with the Calvary United Methodist Church Festival Choir on Saturday afternoon (https://www.facebook.com/events/1825036400948324/), then attended the Pittsburgh Symphony/Mendelssohn Choir performance Saturday night (https://pittsburghsymphony.org/production/56154/handels-messiah). That was many hours of The Messiah for one day, though we only sang the first half of it (plus the "Hallelujah Chorus," of course).
We were good, but, realistically, the PSO/Mendelssohn performance was better. They were all professionals and had a much bigger orchestra and many more singers. We were mostly amatures.
I think our tenor soloist (George Milosh) was better than their tenor soloist (Paul Appleby), and our soprano (Anna Singer) was more understandable than their soprano soloist (Rachele Gilmore, who had great tone quality but her diction was lost). I was a little concerned about the PSO hiring a countertenor to sing the alto solos, but Andrey Nemzer was very good, though had a little trouble with a few high notes.
Much as I like Manfred Honeck as the conductor the PSO, many of the choral pieces, except for "Worthy Is the Lamb," were just too fast. Our conductor, Brian Burns, had a much better sense of how the music should be paced.
It was an enjoyable way to spend a Saturday. I hadn't been singing with choirs very much the last few years, due to severe insomnia and some throat problems. It was great to find the Calvary group.